CO2-free high-purity ethylene from electroreduction of CO2 with 4% solar-to-ethylene and 10% solar-to-carbon efficiencies

C2H4 is an essential precursor for synthesis of a range of industrial chemicals while contributing similar to 150 Mt of CO(2)e emissions per year C2H4 synthesis via electrochemical CO2 reduction reaction (CO2RR) is an attractive approach to reduce carbon emissions. The lower single-pass conversion (<10%) of the state-of-the-art CO2 electrolyzers contributes significantly to the cost of post-CO2RR separation of products, rendering even processes with high CO2RR current densities unfit for scaling up. Here, we develop an aqueous flow-through electrochemical cell to enhance the activity and selectivity of C2H4 on a three-dimensional (3D) Cu mesh electrode by applying square-wave oscillating potentials. A high C2H4 faradaic efficiency of similar to 58%, C2H4 current density of 306 mA/cm(2), and gaseous C2H4 purity of similar to 52 wt % without CO2 in the product stream are obtained. Integrating the 3D Cu mesh catalyst in a photovoltaic (PV) electrolyzer yields a solar-to-carbon (STC) efficiency of similar to 10% with a solar-to-C2H4 efficiency of similar to 4%.